maxair fan size

A Maxxair fits into a 400x400 roof aperture. That’s the size of the hole cut into the steel top of the van. I replaced the middle roof vent in the Kemerton and Kemerton XL with a Maxxair. In both cases it was a Remis 400x400 that AS had fitted, most likely the same in the Kingham. 

If you’re able to fish cable through the gap between the ceiling lining and the steel top of the van then you should be able to reach a convenient 12V feed for the Maxxair. I used the feed for the extractor fan above the hob for the Kemerton installations, but in the thread linked below you’ll see that a Kingham owner (Solaris) used a 12V feed from the TV socket in the wardrobe area.

Tim

https://www.autosleeper-ownersforum.com/t31369-replacing-a-remis-roof-vent-with-a-fan-vent